1. Field of the Invention
The present invention relates to a liquid crystal display device for a laptop or note book type personal computer or word processor, and more particularly, to a liquid crystal display device having a uniform display surface and an improved display quality.
2. Description of the Related Art
FIGS. 1 and 2 show a conventional backlighted liquid crystal display device. In the figures, reference symbol 1 denotes a liquid crystal display plate; 2, an illuminating device (a back light); 21, a light source, such as a cold cathode tube (CCFT); 3, a light guide tube made of a transparent material; 4, a chassis made of a plastic; 22 and 23, plastic holding members for holding the light source 21; and 5, a metal frame (a metal bezel) for covering the four sides of the entire device.
In the conventional liquid crystal display device, the liquid crystal display plate 1 and the light source 21 are covered by the single frame member 5, and transfer of heat occurs between the liquid crystal display plate 1 and the illumination device 2. Thus, when the light source 21 is turned on, the generated heat transfers through or stays inside the frame member 5, increasing the temperature of the frame member 5. Such a heat reaches the liquid crystal display plate 21. The liquid crystal display plate 21 is characterized in that the threshold voltage thereof varies due to a fine temperature difference. Thus, when a temperature difference occurs between the portion of the liquid crystal display plate 1 near the light source 1 and the portion thereof which is located at a distance from the liquid crystal display plate 1, the liquid crystal display plate 1 has an irregular display density and hence the display quality thereof deteriorates.